Recently bought a ball with a Turbo Switch grip thumb installed.

What's the best/easiest way to remove it?
Thin flat screw driver tapped down between sleeve and ball?

I don't have a 1.5" bit to drill out.

Thanks!

Use a large flat head screwdriver or a small chisel and go down the wall of the Switch Grip splitting it.  Do this on 2 sides.  Use the screwdriver or chisel to also cut through the bottom.  By the time you do this it will usually have broken the glue loose and the 2 pieces will come right out. 

to me it's a flathead scredriver and a mallet.

If you have to do them regularly take an old flat head screwdriver and grind a "V" into the tip.  So the tip looks like a "W", not a "V".  This will make it easy to split the wall and it won't keep slipping as you tap it with the hammer.  It's faster than drilling them out and way easier than trying to pry them out.

We take our 1-7/16" IT bit and drill out the SG locking mechanism, this will loosen up the glue on the outer, and then twist out the outer with pliers with minimal force.